While the state’s oil and natural gas industry activity has picked up in recent years, Oklahoma also has experienced an unexplained swarm of earthquakes.
More than 220 earthquakes magnitude 2.5 or higher were reported in Oklahoma in 2013 — more than any other year in state history.
The Oklahoma Geological Survey, the U.S. Geological Survey and others have been studying whether the state’s swarm of quakes over the past few years is connected to water injection wells. The average oil well in Oklahoma produces about 10 times as much saltwater as oil. Most of that water is returned deep underground through saltwater disposal wells.
One report co-authored by a former University of Oklahoma professor and a U.S. Geological Survey researcher connected the state record 5.7 magnitude quake in 2011 to an injection well near Luther, but the Oklahoma Geological survey has said the incident appears “consistent with a natural earthquake.”
Injection and disposal wells have been used for much of the state’s history. While oil and natural gas activity has picked up in Oklahoma in recent years, oil and water production still pale compared to levels seen in the 1980s and 1920s.